An overview of different transparent conductors is given. In addition, atmospheric pressure CVD of ZnO resulted in
conductivities below 1 mΩ cm for a temperature of 480°C, whereas at a process temperature of 200°C a value of 2 mΩ
cm was obtained. Also atmospheric pressure spatial ALD was used to make conductive ZnO. Furthermore, the properties of transparent conductive oxides (TCO) can be enhanced by application of metallic grids. This way, sheet resistances of below 0.1 Ω/sq and transmittances above 85 % can be achieved. Modeling indicates that the performance of thin film cells can be enhanced by18% using a grid/TCO combination. Light scattering is a vital element of thin film solar cells and both texturization and multimaterial approaches for advanced light management such as plasmonics are discussed.
The acceptance of solar cells in the built environment is partly dependent on the appearance of the solar modules. One
aspect in the appearance is color. In most cases a solar cell itself reflects either blue or no color and will appear blackish.
For the blue solar cells it is possible to tune the antireflection layer in such a way that a different color is reflected. We
propose a front-sheet covered with a stack of thin layers consisting of high and low refractive index materials deposited
from sol-gel onto PET foil such that only a particular wavelength range is reflected. We show through modeling that by
alternating layers consisting of low refractive index layer (silica (SiO<sub>2</sub>) and high reflection layer (silica-titania 25 mol%
SiO<sub>2</sub>: 75 mol%TiO<sub>2</sub>) on PET foil such color reflection can be achieved. In modeling exercises the influence of the
number of layers, thickness variations and angle of incidence on the reflected color are predicted as well as an estimated
influence on the module efficiency. We show that with a four layer stack we can reach chroma values of 60 for green
and 40 for red color in the CIELCH system. In experimental results we achieve a peak reflection of 41.7% with a band
width of 90 nm while transmission is more than 90% for the other parts of the spectrum.
Organic flexible electronics is an emerging technology with huge potential growth in the future which is likely to open
up a complete new series of potential applications such as flexible OLED-based displays, urban commercial signage, and
flexible electronic paper. The transistor is the fundamental building block of all these applications. A key challenge in
patterning transistors on flexible plastic substrates stems from the in-plane nonlinear deformations as a consequence of
foil expansion/shrinkage, moisture uptake, baking etc. during various processing steps.
Optical maskless lithography is one of the potential candidates for compensating for these foil distortions by in-situ
adjustment prior to exposure of the new layer image with respect to the already patterned layers. Maskless lithography
also brings the added value of reducing the cost-of-ownership related to traditional mask-based tools by eliminating the
need for expensive masks. For the purpose of this paper, single-layer maskless exposures at 355 nm were performed on
gold-coated poly(ethylenenaphthalate) (PEN) flexible substrates temporarily attached to rigid carriers to ensure
dimensional stability during processing. Two positive photoresists were employed for this study and the results on plastic
foils were benchmarked against maskless as well as mask-based (ASML PAS 5500/100D stepper) exposures on silicon
Photonic crystal (PC) devices in the InP/InGaAsP/InP planar waveguide system exhibiting narrow bandwidth
features were investigated for use as ultrasmall and tunable building blocks for photonic integrated circuits at
the telecom wavelength of 1.55 μm. The H1 cavity, consisting of a single PC-hole left unetched, represents
the smallest possible cavity in a dielectric material. The tuning of this cavity by temperature was investigated
under the conditions as etched and after the holes were infiltrated with liquid crystal (LC), thus separating the
contributions of host semiconductor and LC-infill. The shift and tuning by temperature of the MiniStopBand
(MSB) in a W3 waveguide, consisting of three rows of holes left unetched, was observed after infiltrating the PC
with LC. The samples finally underwent a third processing step of local wet underetching the PC to leave an
InGaAsP membrane structure, which was optically assessed through the ridge waveguides that remained after
the under etch and by SNOM-probing.